Nowadays, it is becoming more popular to use a computer by incorporating another small computer, such as an accelerator, therein rather than to use a computer independently.
As an application of an incorporated system, for instance, a circuit dedicated for image processing is mounted on a computer, or an incorporated device makes calculations using data having a large volume, such as big data.
In such cases, it is desirable that a sufficiently large bus width be provided between the computer and an incorporated device, and a sufficient transfer speed of data be ensured.
However, even when the performance of the incorporated device is high, there are cases that it is difficult to provide a sufficiently large bus width, which makes it difficult for the bus to achieve a sufficient transfer speed particularly when large data is to be treated.
In addition to the bus width, some other causes may lead to an insufficient transfer speed. Meanwhile, when large data, particularly large image data, is used, it is not known whether or not all the data is necessary for calculation, and there is a possibility that transfer of unnecessary data is performed. A Similar problem occurs in not only the relationship between a main computer and an incorporated system, but also transfer between architectures within the incorporated system, for instance, transfer between a module specialized for filter processing and a memory module.